Automatically-adjustable brush-holder.



W. J. RICHARDS. AUTOMATICALLY ADJUSTABLE BRUSH HOLDER. APPLICATION FILEDSEPT. 10 1900.

Patented 90%;. 13, 1908.

2 SHEETS-sham 1.

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I A urn n {Q g 5 I i i W. J. RIUHARDS. AUTOMATICALLY ADJUSTABLE BRUSHHOLDER. APPLICATION FILED SBPT.10,1900.

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Patented Oct. 13, 1908.

lnr/emZZz z WALTER J. RIOEAR so. ceases.

' c all whom it may concerns Be it known that l, WALTER- J. Rroneaes,resident of liilwaukee, in the county of Milwaukee and State ofWisconsin, have he ented a certain new and useful Automaticfollowing isa specification. J

My invention relates to what are co nmonly known in the electric art asbrush holdersanrl the object thereof is to provide a brush holderwhichshallbe automatic in action and to devise-a simple and efficient con-Sfil'uction attaining. that result. i I

It is Well known that, in a motor, the best plane of commutation isslightly heel: of the short ,circuited hy the commutator brushes, rmelectromotive force would be generated 1 {that not onlywill "overcomethe self in 1luc-- tion of thecurrent to. be reversed, but else willestablish in the said shortcircuited coils a flow of current in the samedirection as the ireverscdcurrent, As is also well known in l mosabuttheubest plane oi commutation is forward oi'the neutral plane,

1in a-propcrly designed motor running un- -1 cle'rno load, the neutralplane may be de fined asthe plane extending lengthwise. of the'armaturen'iidway hetweenthe poles, and. inay be said to he the plane of nomagnetism. It is also a fact that the current passing liro'ogh thearmature windings has a distorting effect on this neutral plane, in thes5 fc'ase'of a motor the ne-utral plane sluiti'ng backward opposite tothe direction of rota tion of the armature. In electrical motors runningcontinuously in one direction, the brushes are perm anently set asfavorably as possible for the articular conditions under which the maciies are running. In reso'set permanently in the best possibleposition,inasmuch as the neutral planeshifts in tion in Whicheverdirection the motor may he ,run, that is a brush capable of followingupv the shifting of the neutral plane, thereby us, or MILWAUKEE,WisooN-siu, Assisuoc 'i o ALLIS-OHALMERS, COMPANY, A cosroiairrion orNEW messy.

Speeificetion of Letters Patent.

ally-Adjustable, Brush-Holder, ,0? which the neutral plane where, inthose arinaterecoils v other-art,'.siniilar actions talu place, in(lyric vie'rsihlc motors, such as motors operating. cranes, elevators,etc, the brushes cannot be "the one direction or the other according toAUTQMATIUALLY-ALZDJUSTATBLE BRUSH HQLDERQ recanted Oct. is, ,reoe.

Application illezl Seirtemher 10, 1900. Serial No. 29,5'3'1.

maintainiug the non-sparlzing position of commutation.

In the drawings, Figure 1 .is a plan View 0.1 a portion of an electricmotor-with my brush applied Fig. 2 a side elevation thereof; Fig. "Sanend view thereof; and Figs. 4, 5 and 5 views of modified forms ofconstruction.

The usual commutator, 1 has a shaft 2, shaft hearing 3 and hearing box4. A brush holder yoke or support 5 is secured to the .box and carriesat its outer end a rod or stud 6 fastened to such yoke by the nut 7 andinsulated from the yoke by insulating hush iugs 8. in this manner therorl is helrl rigany to theyolie but insulated therefrom.

A home having the two arms 9 is pivoted at one earl upon the stud andhetween the outer end oii'these arms is carried a brush holder 10. Thisholder which is preferehly rectangular and open at top and bottom, ispivoted to the arms 9 by the rivets ill or otherwise so as to be free toturn. The ex.- treme ends {Poi the armspreierably, though notnecessarily, bend substantially at right angles, and. downward Whenbeyond their pivotal 'point as isiclearly shown in Fig. 32 Obviouslyequivalent constructions may he adopted. Suitable tension is appliedupon the frame to hold the same towardsthe cornmutator and. shown. Iemploy a coiled leaf spring 12 fastened at one end to 'therod 5 andbearing upon a cross piece or hridge 13 between the arms 9Q The brush,or more accurately speaking the carbon, consists'of'a piece orblock orcarbon 14 held within the carbon. holder by the set screw 15 which bearsagainst the intermediate clamping plate 16. This brush is presentedsubstantially end on to the commutator, T he contacting end of the 4'carbon brush has, on either side of its central axis, the cylindricalsurfaces 17 and 18 whose radii are equal to the radiusof the commutator,these surfaces of necessity assuming this shape or are on account of thewearing oi the carbon against the commutator.

The exterior of the brush holder on two opposite-sides is provided witha pair of legs or projections 19 and .20 which are res ectivelycontacted by the arms 9 zecorcing to whichever face .17 or 18 isContacting' the armature. The brush holder is so set that a centralclone inthe carbon extending par allel with the rod 6 andperpendicularly to the commutator rests upon that portion of thecommutator which is directly connected to the armature conductors lyingmidway between the poles. 7

While I prefer to use and. have herein shown the lugs 19 and 20 locatedon the car- Theo eration of my brush holder is as fol-- hen the armatureis rotating anti-' lows: clockwise, that is in the direction of thearrow-in Fig. 3, and there being friction between the,carbon and thecommutator due to the tension of the spring, the carbon is retatedaboutthe axis of its holder until the arms 9 contact the lugs 19. Theresult is that the portion 17 of the carbon seats on the commutator onthe right hand of the shifted neutral plane, or approximately thereto,inasmuch as the amount of shifting is proportional to the load on themotor. Conseuently when in the claims it is stated that t e carbon seatsbehind the shifted neutral plane, it may be thus or approximate thereto."The carbon has thus been automatically adjusted to the proper and mostfavorable position on the commutator for non-sparking. When the armaturerotates clockwise, the carbon is rotated about the axis of its holderuntil the arms 9* are contacted by the lugs 20 at which time the portion18 will have a seating against the commutator on the left hand side orapproximate thereto (Fig. 3) of the above mentioned neutral plane which.has shifted as above described.

To adapt it to the requirements of a reversing motor, the carbon isconsiderabl,

wider than that permanently set on commutators running continuously inone direction, inasmuch as only one-half of the contacting end of mycarbon is in service at any one time. It will be evident that thegreater the desired shifting of the carbon the greater must be the widththereof.

While I prefer to use a single block of carbon with its two surfaces 17and 18 it is eviderit that it may be split up into two separate pieceswithout departing from the s )irit of my invention. lln Fig. 4 l haveilustrated such division and also the changed construction necessary. Inthis form, the carbon holder 21 is adapted to receive the two carbons 22and :23, the former being held therein by set screw 24 and clampingplate 25 and the latter by set screw 26 and clamping plate 27. Thecarbon holder may be pivoted in substantially the same Tnanner-as shownin Figs. l to 3. Manilcstly the curbons may be located in grcnteror lessproX- imity to each other, provided, however, the

distance separatin t ie two carbons is kept within reasonable limits.The 0 cration'of the construction just described 13 substantially thesame as that of the other already described.

Figs. 5 and 6 show a modified form of con struction of the brush holderand its supp orting frame but embodying the same principles and mode ofoperation as the other forms. The housing 28 preferably rectangular hasa shank 29 for attachment-to any suitable support. In a carbon holder 30is secured b set screws 3l'the carbon 32. This holder as on two oppositesides trunnions 33 fitting snugly but not tightly in slots 34 which areradialof the commutator, whereby the holder is loosely contained withinthe housing. A hammer 35 is pivoted to the ,arms 36 projecting u wardlyfrom the housing and is downward y curved at its free end so as to restupon the trunnions. This hammer is downwardly pressed by the springs 37and the pressure is ultimately transmitted to the carbon in a directionperpendicular to the commutator. A flexible conductor 38 connects theholder with the housing. The holder is adapted to turn on its trunmonsuntil its lower end contacts the housing at 39 when the armature isrotating in one direction or at 40 when rotating in the oppositedirection. The operation of this form is substantially the same as'thatof the other forms. i

already described. It will be understood that I do not confine myinvention to the use of carbon-inasmuch as any conducting materialsuitable for the purpose may be used, furthermore, the term brush isemployed herein in a broad generic sense as meaning any conductor fortaking the current from the commutator;

My brush or carbon thus has a changed. position of contact on thecommutator whenever the direction of rotation is changed. .ln-

asmuch as, in a motor, the neutral plane shifts backward, my brush isconstructed so as to obtain a seating on the commutator at a pointbehind this shifted neutral plane and to automatically adapt itself tothe changes incident to the change in direction of rotation. Toaccomplish these results, the brush is so pivoted as that its contactingsurfaces have, with respect to the commutator, a tangentiality in adirection opposite or against the direction of rotation of thecommutator.

1 claim: l. The combination with a reversible motor and its commutator,of a pivoted brush holder, and a brush adjustubly arrangedin said holderand having two separate contactsconce their ceutral'longitudinal axes,which pass through said contacting surfaces, parallel to each other.

with a reversible motor and its commutator, a pivoted-frame, a carbonholder pivoted 1n such frame, a single carbon arranged in such holderand having difierent commutatingsurfaces which are adapted to be fedradially or end on to the commutator, said carbon bein automaticallyadjustable according to the. irectionof rotation of the commutator topresent one or the other of such surfaces on one or the other side ofthe shifted neutral plane but always behind such plane or approximatethereto.

3. A brush comprising, in combination with a commutator a carbonpressing on the commutator, a holder therefor, lugs or stops on theholder, and a frame intermediate of 'whose length the holder is pivoted,the frame extending between such in s to limit the relative movements ofthe holder and frame.

4. A brush comprising in combination with a support, a stud orrodmounted thereon, a frame pivoted on such stud, a carbon holder pivotedtothe frame, a carbonarranged in such holder, and having two contactingsurfaces from the center outwards and on the same are of a circle as thecommutator, means for secuiin the carbon in the holder and means forhmiting the pivotal movement of the holder in either direction with resect to the frame.

5. A rush comprising, in combination with a sup ort, a stud. or rodmounted thereon, a dou e armed frame pivoted at one end to the stud, acarbon holder 1pivotally mounted near the free ends of t arms of suchframe and provided with pairs of exterior lugs on the sides on which itis pivoted, the extreme free ends of said arms being extended downwardlysubstantially at right angles Sit below the point on which the holder ispivoted and between the-pairs of lugs, and a carbon in the holder.

6. A brush com rising a pivoted frame 9, having angled on s 9, a carbonholder 10 pivoted to the frame at 11 and havin pairs clamping late inthe holder, and a set screw passing t irough the holder and. bearingagainst the plate, the ends 9 of the frame pert to insulate the studtherefrom, a frame pivoted on the stud and having parallel arms 9 whoseextreme ends 9 are extended substantially at right angles, a cross piece13 between the arms, a carbon holder 10 pivotally mounted between thearms of such frame, a carbon in such holder and a coiled leaf springwhose coiled end is rigidly secured to the stud-and whose other endbears upon said cross piece to depress theframe and the carbon holderand carbon.

8. In combination with a reversible motor and its commutator, a brushcomprising. a pivoted carbon holder and a single carbon adjustablyretained therein having on its end adjacent to the commutator the twocontact ing surfaces 17 and 18 presentable to the commutator on eitherside of the shifted neutral plane of the commutator but therebehind orapproximate thereto, such surfaces being always presented in atangential direction opposite to the direction of rotation of thecommutator and the body of the carbon being directed substantiallyradially of the commutator; I

WALTER J. RICHARDS.

Witnesses:

GEORGE ELLEsoN, R. L. GRUBER.

. of lugs 19 and 20, a carbon inthe ho der, a 2. A brush comprising, incombination

